Nissan micra failed emissions test - isobelle
My much-loved 1998 micra failed its MOT on the emissions test.

The garage say that it might be a sensor (can't remember the name but it started with L and had something to do with air!) or, in the worst case, it might be the cat converter.

I just wondered if anyone has had a similar experience and the liklihood of it being the converter. If it is the converter, am I going to need a second mortgage? It goes in for investigation tomorrow :(
Nissan micra failed emissions test - RichardW
Lambda sensor - it senses the amount of oxygen in the exhaust.

What sort of driving do you normally do? If it's mostly short trips around town it may just be a bit gunged up, so before you take it back take it for a good hard run (like 40 or 50 miles and make sure you run it at high revs for a good deal of the time - otherwise known as an Italian Tune Up) - then ask them to retest the emissions BEFORE they do anything else. This may cure it.

It's unlikely to be the cat on a 5 year old car, but nothing's impossible. The coolant temperature sensor is another strong possibility. As long as your garage are decent at fault finding you should get away with not too much cost.


Is it illogical? It must be Citroen....
Nissan micra failed emissions test - John24
If it is your lambda sensor replacement part should cost you about £50 plus fitting, which shouldn't amount to much. However, Richard W's advice is good, take your car for a fast drive to blow out the cobwebs before you submit it for a check. If it turns out to be the 'cat' this should cost between £120 and £160 plus fitting depending on particular model.
Nissan micra failed emissions test - isobelle
Thanks John and Richard for such quick replies!

The car does about 80 miles a day on the motorway, although it had been idle for a couple of days just prior to the test so I will ask them to double check as you suggest.

Even if it is worst case scenario I'm encouraged by your advice...the way the mechanic was shaking his head I thought a cat converter was going to cost roughly the value of the car!

Again - many thanks, I can rest a bit easier now :)
Nissan micra failed emissions test - Aprilia
For parts try:

Micra catalyst is £100-150 depending on quality, they also do lambda sensors for about £40 I think.
Nissan micra failed emissions test - Reggie
When my sons 106 failed, I gave the car an Italian tune up (a right good thrashing) and used a propriatery injection cleaner. I don't know which one did the trick, but it passed its emission test with no further attention on the second test.
It costs about £10 for the cleaner which I have to say, I was a bit sceptical about.
Nissan micra failed emissions test - Indy
Yesterday, our fiesta (93L, 38K, 1.1 injection) failed the emssions test - CO emssions were beyond the permissible range.

I car did only 5K miles for the whole of last year. So, the garage asked me to give it a good whack - I took it for a 20 mile journey along the motorway, never went higher than third gear. Re-tested soon after this, this time the Lambda sensor reading was out on both the idle and fas run.

I have been quoted £60 plus VAT to supply and fit the sensor.

Two questions:
Is this reasonable price to fix it?
Could it be a problem with the cat?

I don't want to spend too much on a car that is not worth a lot - in fact I am MOTing it, so that we can sell it ASAP.

Nissan micra failed emissions test - isobelle
I thought I'd let you know that I got the car back yesterday and the problem turned out to be just a loose connection to the sensor - hooray! My faith in garages is now fully restored (well, THIS one anyway!) so thanks again to everyone for the good advice :)

Ask Honest John

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